This invention relates in general to automatic fastening machines used in continuous production lines, and more particularly, to a fastener supply magazine for permitting rapid replenishment of fasteners without interrupting production.
Automatic fastening machines such as used to drive staples or the like into wooden lattices, pallets, or fence panels, for example, can be multiply mounted side-by-side on a support frame above a surface conveyor which carries the work product beneath the fastener machines, and are actuated by triggering devices responsive to the movement of the work product to a predetermined position to drive staples or other type fasteners into the work product. Such automatic systems generally run at higher speeds than any achievable in manual operation, and expend fasteners at an extremely high rate.
For example, in stapling together the intersections of a lattice, the fastening machines can use up to a thousand staples per minute. The normal supply magazine for an automatic fastening machine holds approximately one hundred and fifty staples and, in such high speed operation, must be reloaded as often as every three minutes. In prior art fastening machines, the staples are fed from the magazine onto a track and are urged toward the driven head by a spring biased pusher in contact with the rearmost staple in the clip or stick of staples. Thus when the staple supply must be replenished, it is necessary that the pusher be retracted to make room for a new stick or clip of staples to be placed on the track or guide means. In order for the pusher to be retracted, it is necessary to interrupt the fastening process and such interruptions which can occur at intervals of about three minutes result in a loss of productivity.
The co-pending U.S. patent application, Ser. No. 882,345, now U.S. Pat. No. 4,728,021 of which the present application is a continuation-in-part, discloses a fastener machine which utilizes a fastener advancing means which operates without the usual pusher and which is open above and behind the fastener clip guide means, thereby allowing new clips of staples or other type fasteners to move by gravity from the fastener magazine onto the guide means, thus obviating the interruption of operation to replenish the supply of staples or other type fasteners. More particularly, the fastener advancing means comprises a fastener guide means upon which clips of staples or other type fasteners from the fastener magazine travel in an upright altitude toward the drive element. The movement of the clips is caused by friction numbers engaging the side surfaces of the fastener clip or stick and which are moved forward toward the drive element on each cycle of operation of the drive element. The friction members then relax and retract until the next cycle, at which time they again engage the sides of the clip and urge it forward. Such action as just described insures that the leading fasteners of the clip is properly positioned beneath the drive element before the drive element is actuated.